The present invention relates to vehicles that employ an axle or axle assembly that pivots relative to said vehicle to permit turning thereof. Specifically, the present invention prevents the axle of a vehicle to pivot beyond a specified angle, which can greatly increase the safety of said vehicle. This invention is therefore of great use for skateboards.
The axle assembly of a skateboard is called a “truck assembly” or simply a “truck.” A skateboard typically comprises an elongated platform with a pair of trucks secured to the underside of said platform at opposite ends. Each truck typically comprises a “baseplate” and a “hanger.” The baseplate is statically secured to the platform. The hanger is secured to the baseplate via a “kingpin” and compressible “bushings” that permit the hanger to pivot relative to the baseplate and platform. The hanger includes an axle to which wheels can be secured. Generally a complete skateboard comprises the platform, two trucks, and four wheels.
The primary direction of travel of a skateboard is along the longitudinal axis of the platform. When riding a skateboard, leaning in a direction generally perpendicular to the direction of travel causes the hangers to pivot relative to the platform and results in the skateboard turning in that direction.
The turning responsiveness of a particular truck is determined by the compressibility of the bushings and how tightly a ring-shaped member of the hanger is sandwiched between said bushings. The adjustability of said turning responsiveness is very important because different skateboarders prefer different turning responsiveness and even the same skateboarder may prefer different turning responsiveness at different times.
There are many skateboard trucks that permit the hanger to pivot via cushions, springs, cams, or struts instead of or in addition to bushings. However, because these trucks deviate greatly in appearance from typical skateboard trucks, they are undesired.
U.S. Pat. No. 6,793,224 (Stratton) discloses a skateboard truck that includes an arm carried by the base and a spring-loaded linkage connected between the base and the arm to bias the arm towards a center position aligned with the skateboard's direction of movement.
U.S. Pat. No. 6,523,837 (Kirkland) discloses an adjustable truck assembly for skateboards with a retainer that provides a large turning radius for the axle, a highly predictable turning performance, and tool-less adjustment of the turning performance.
U.S. Pat. No. 6,315,304 (Kirkland et. al.) discloses an adjustable truck assembly for a skateboard, which generally comprises an axle housing, a base, a kingpin connecting the axle housing and base, a turning mechanism between the axle housing and base around the kingpin consisting of opposed cam surfaces that are angled along the axis of the kingpin and an elastomeric bushing so that rotating the axle housing about the kingpin pushes the cam surfaces apart against the compression pressure of the elastomeric bushing, and an adjustment mechanism for adjusting the pressure against the bushing.
U.S. Pat. No. 6,224,076 (Kent) and U.S. Pat. No. D439,945 (Kent) disclose a pneumatic compression strut skateboard truck that utilizes a pneumatic compression strut suspension system, which is of the same type and kind used in automobiles and other mechanical devices employing shock absorbing technology.
U.S. Pat. No. 5,971,411 (Jones and Jones) discloses a skateboard truck, which generally comprises an extruded skateboard truck base that has an angled aperture for a cushion on which a hanger rests and a pivot bolt that holds the hanger to the base and that allows weight placed on either side of the skateboard to put pressure on the cushion to facilitate a turn.
U.S. Pat. No. 5,263,725 (Gesmer and Haug) discloses a skateboard truck that incorporates exceptionally rapid and consistently accurate axle rebound to the straight-ahead position, consistent and predictable steering response, an improved balance between stability and maneuverability, fine steering control, and a wide range of steering radii, which generally comprises a yoke, a pivot pin, and coil springs.
U.S. Pat. No. 4,251,087 (Hansen) discloses a truck apparatus for skate and skateboard devices, which generally comprises an elongated kingpin, a means for affixing the upper end of the kingpin to the bottom of a load carrying platform, a wheel axle carriage assembly pivotally affixed to the lower end of the kingpin and adapted to rotate about the axis of the kingpin, a resilient drag sleeve and turn restoring element compressively disposed between the first and second friction surfaces, and a lock nut for selectively urging the carriage assembly towards the mid-portioned member so as to compress the drag sleeve between the first and second friction surfaces such that the carriage assembly may be resistively and partially resiliently rotated about the axis of the kingpin.
U.S. Pat. No. 4,185,847 (Johnson) and U.S. Pat. No. 4,176,850 (Johnson) disclose skateboard trucks that carry a plurality of wheels mounted in independent suspension, which generally comprise longitudinally extending arms that carry the wheel axles forwardly or rearwardly relative to a mounting that secures the arms in rotatable fashion to the trucks and that are resiliently biased by means of separate springs or torsion bars.
U.S. Pat. No. 4,184,693 (Whitmarsh) discloses a skateboard truck, which generally comprises a base plate for securing to the underside of a skateboard platform and a spring member, such as a plate spring, that is joined to the base plate by one end and carries a wheel axle near an opposite end.
U.S. Pat. No. 4,152,001 (Christianson) discloses a truck for a skateboard or the like, which generally comprises an S-shaped leaf spring that attaches to the skateboard and, through a pivot pin, carries a transverse axle-supporting member at the opposite end and further generally comprises a pair of upwardly and inwardly inclined compression springs that are engaged by a pin carried by the leaf spring to resist pivotal movement of the leaf spring relative to the axle-supporting member.
An undesired characteristic of skateboard trucks is “wheel bite,” which occurs when the hanger pivots relative to the platform until a wheel contacts the underside of the platform. When wheel bite occurs, the contacting wheel stops rotating and the skateboard rapidly stops moving, usually causing the skateboarder to fall. In skateboard trucks that employ only bushings, currently the only way to prevent wheel bite is to more tightly sandwich the ring-shaped member of the hanger between the bushings. However, this greatly decreases the turning responsiveness of the truck, and is therefore highly undesired.
U.S. Pat. No. 6,547,262 (Yamada and Hiranuma) discloses a skateboard truck assembly in which the pivot arm of the truck hanger rotates freely in a bearing assembly supporting the pivot arm in the socket hub.
U.S. Pat. No. 6,474,666 (Andersen and Andersen) discloses a shock-absorbing skate truck assembly that includes a resilient shock absorber at the kingpin located between the assembly base of the assembly and the axle support member for absorbing shocks encountered during use and another shock absorber that is located in a recess of the assembly base and is engaged by an axle support member arm.
U.S. Pat. No. 6,443,471 (Mullen) discloses a truck assembly configured to eliminate undesired ride characteristics such as hanger-jiggle and wheel bite without sacrificing the skateboard's steering responsiveness, which generally comprises an axle assembly with a ring-shaped hanger that is confined on a kingpin using a pair of bushings, at least one of which includes an annular flange that projects into an annular gap that is defined between the hanger and the kingpin.
U.S. Pat. No. 6,428,023 (Reyes and Horn) and U.S. Pat. No. 6,315,312 (Reyes and Horn) disclose a truck assembly including a housing adapted to be mounted to a skateboard or the like, which generally comprises an axle bracket that is mounted for rotation transverse to the longitudinal axis and that includes a projecting upper end portion and a bottom end portion adapted to receive a transversely extending axle and wheel assembly, a resilient member located at least partially in the housing that is adapted to resist transverse rotation of the axle bracket and provide a restoring force, and a wedge member that has an aperture configured for receiving the projecting upper end portion of the axle bracket to establish a direct coupling therebetween.
U.S. Pat. No. 6,367,819 (Andersen and Andersen) discloses a shock-absorbing skate truck assembly including a resilient shock absorber at the kingpin located between the assembly base of the assembly and the axle support member for absorbing shocks encountered during use.
U.S. Pat. No. 6,318,739 (Fehn, Jr.) discloses a suspension assembly for a skateboard which generally comprises a base plate with a truck plate pivotally attached at one end with a shock absorber located between the base plate and the truck plate and further with a projection on the base plate that protects the shock absorber and aids the rider in performing tricks.
U.S. Pat. No. 6,182,987 (Bryant) discloses a truck assembly with replaceable axles and ball joint pivots that incorporates precision steering and rocking components for consistency and accuracy during maneuvers, a method for removing or replacing worn or broken axles, and a precision ball pivot pin that acts as the associate pivotal and rocking mechanism for the truck assembly.
U.S. Pat. No. 4,398,734 (Barnard) discloses a truck design for a skate-type device involving turning and tilting axes of rotation, which generally comprises a T-shaped rod, the top part being housed in a base plate and the leg passing through a slot in the base plate, a resilient pad, washers, an axle yoke, and an adjustable lock nut.
U.S. Pat. No. 4,166,629 (List) discloses a skateboard truck, which generally comprises a base that has a first portion with a first hole therein and a second portion with a second hole therethrough, a hanger that has an axle for mounting wheels thereon, a ring and a pin, the pin being received in the first hole, and a coupling assembly for coupling the hanger to the base.
U.S. Pat. No. 4,103,917 (Widolf) discloses a skateboard truck, which generally includes a wheel housing resiliently mounted on a skateboard truck base by means of a fastener which extends through the housing and is threaded onto a stud fixed to the base to compress a tubular cushion between the housing and the base, in which the fastener has a square cross-section that mates with a square bore in the cushion so that rotation of the fastener with respect to the cushion is prevented except when the retainer is manually and forceably rotated to adjust the compression on the cushion.
Although U.S. Pat. No. 6,443,471 (Mullen) claims to solve wheel bite by teaching a bushing with an annular flange, the bushing is comprised of a soft material and is therefore not effective at preventing wheel bite. Furthermore, any achieved wheel bite prevention relies on how tightly the ring-shaped member of the hanger is sandwiched between the bushings, and therefore affects the turning responsiveness of the truck.
Accordingly, what is desired, and has not heretofore been developed, is a skateboard truck that prevents wheel bite without affecting the turning responsiveness thereof. It is further desired that the skateboard truck maintain the basic appearance of a typical skateboard truck. Finally, it is desired that the amount of wheel bite prevention be adjustable by the user.